Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030288AbVKHEeA (ORCPT ); Mon, 7 Nov 2005 23:34:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030289AbVKHEeA (ORCPT ); Mon, 7 Nov 2005 23:34:00 -0500 Received: from mailout1.vmware.com ([65.113.40.130]:28179 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S1030288AbVKHEd7 (ORCPT ); Mon, 7 Nov 2005 23:33:59 -0500 Date: Mon, 7 Nov 2005 20:33:58 -0800 Message-Id: <200511080433.jA84Xwm7009921@zach-dev.vmware.com> Subject: [PATCH 14/21] i386 Apm is on cpu zero only From: Zachary Amsden To: Andrew Morton , Chris Wright , Linus Torvalds , Linux Kernel Mailing List , Virtualization Mailing List , "H. Peter Anvin" , Zwane Mwaikambo , Martin Bligh , Pratap Subrahmanyam , Christopher Li , "Eric W. Biederman" , Ingo Molnar , Zachary Amsden , Zachary Amsden X-OriginalArrivalTime: 08 Nov 2005 04:33:58.0360 (UTC) FILETIME=[A2A16D80:01C5E41D] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2063 Lines: 52 APM BIOS code has a protective wrapper that runs it only on CPU zero. Thus, no need to set APM BIOS segments in the GDT for other CPUs. Signed-off-by: Zachary Amsden Index: linux-2.6.14-zach-work/arch/i386/kernel/apm.c =================================================================== --- linux-2.6.14-zach-work.orig/arch/i386/kernel/apm.c 2005-11-07 10:17:45.000000000 -0800 +++ linux-2.6.14-zach-work/arch/i386/kernel/apm.c 2005-11-07 13:36:05.000000000 -0800 @@ -2170,8 +2170,8 @@ static struct dmi_system_id __initdata a static int __init apm_init(void) { struct proc_dir_entry *apm_proc; + struct desc_struct *gdt; int ret; - int i; dmi_check_system(apm_dmi_table); @@ -2253,18 +2253,17 @@ static int __init apm_init(void) * not restrict themselves to their claimed limit. When this happens, * they will cause a segmentation violation in the kernel at boot time. * Most BIOS's, however, will respect a 64k limit, so we use that. + * + * Note we only set APM segments on CPU zero, since we pin the APM + * code to that CPU. */ - for (i = 0; i < NR_CPUS; i++) { - struct desc_struct *gdt = get_cpu_gdt_table(i); - if (!gdt) - continue; - set_base(&gdt[APM_CS >> 3], - __va((unsigned long)apm_info.bios.cseg << 4)); - set_base(&gdt[APM_CS_16 >> 3], - __va((unsigned long)apm_info.bios.cseg_16 << 4)); - set_base(&gdt[APM_DS >> 3], - __va((unsigned long)apm_info.bios.dseg << 4)); - } + gdt = get_cpu_gdt_table(0); + set_base(&gdt[APM_CS >> 3], + __va((unsigned long)apm_info.bios.cseg << 4)); + set_base(&gdt[APM_CS_16 >> 3], + __va((unsigned long)apm_info.bios.cseg_16 << 4)); + set_base(&gdt[APM_DS >> 3], + __va((unsigned long)apm_info.bios.dseg << 4)); apm_proc = create_proc_info_entry("apm", 0, NULL, apm_get_info); if (apm_proc) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/